Factors affecting the rate of deterioration in the frying qualities of fats. 1 i. exposure to air

The effect of heating fats in air and the effect of heating fats in an inert atmosphere were compared, and the relationship of air to changes in the frying characteristics of fat studied. The frying characteristics of a fat did not change to an extent that is commercially significant even after 48 hr heating at 375F in the absence of air; fats heated under identical conditions but in the presence of air, changed radically. It was found, also, that fat which had changed appreciably in frying characteristics when heated in air did not continue to change significantly when heated further under nitrogen. Hence, presence of oxygen was shown to be a necessary condition for the deterioration of the frying qualities of fat at frying temp. Rate of change of the frying characteristics was found to be directly proportional to the degree of exposure of fat surface to the oxygen.